Electric equipment for mining machines



N. D. LEVIN April 11, 1933.

ELECTRIC EQUIPMENT FOR MINING MACHINES Filed Dec. 5, 1929 2 Sheets-Sheet 1 N. D. LEVIN April 11, 1933.

ELECTRIC EQUIPMENT FOR MINING MACHINES 2 Sheets-Sheet 2 Filed Dec. 5, 1929 /N VEN TOR Ni/s D. Lev/n.

Patented Apr. 11, 1933 NILS D. LEVIN, OF

COLUMBUS, OHIO, ASSIGNOR TO THE JEFFREY MANUFACTURING COMPANY, OF COLUMBUS, OHIO, A CORPORATION OF OHIO ELECTRIC EQUIPMENT FOR MINING MACHINES Application filed December 3, 1929. Serial No. 411,335.

The present invention relates to certain new and useful improvements in electrical equipment for mining machines of the type, as herein embodied, adapted to rest upon and slide over the floor of a mine during the min ing operations, or to be loaded upon a suitable track supported and guided truck for transportation from one working place to another, the truck during the said. mining operations serving as an operating base for the mining machine.

The especial object of this invention is to provide an improved arrangement of parts whereby line potential will be entirely exeluded from the motor When it is not in operation, thereby rendering possible such handling of the motor and its adjuncts, as may be necessary in effecting adjustments or repairs.

Another object is to provide mechanism mounted upon the truck and controlled from the mining machine, for the safe and efficient interruption of the heavy electric currents necessary for the satisfactory operation of.

the machine.

Another object is to provide improved automatically acting means for the protection of the electrical equipment of the machine from the destructive effects of excessive currents resulting from overloads, shortcircuits or the like.

An illustrative embodiment of the means whereby I attain these and other objects is fully set forth in the following specification and shown in the accompanying drawings in which:

Figure 1 is a diagrammatic elevational view of a mining machine and its accompanying truck of the type to which my present invention is particularly applicable.

Figure 2 is a diagram of the electric circuits involved in the invention emphasizing the relative location of the various elements, and

Figure 3 is a compact trio circuits.

In the power installations of coal mines it is customary to connect the negative side diagram of the elecof the electric circuit with the rails of the mine track whereby connecting it with the ground which serves as a return conductor. It has heretofore been the practice to connect the controlling devices into the electric circuits of the mining machines between the positive supply conductor and the motor to thereby cut off line potential from the motor when it is not in operation, and thereby render possible such handling of the motor as may be necessary for its adjustment or repair. This arrangement has been found unsatisfactory because, due to the difference of potential between the electric contacts of the controller and its grounded casing, there is a tendency for arcs formed at these contacts to jump to the casing, sometimes causing serious short circuits. The space available upon the mining machine restricts the size of the controller, and its parts cannot be made large enough to efiiciently break currents of the magnitude required to satisfactorily operate the mining machine. To protect the apparatus from excessive currents it has been customary to provide a fuse in the circuit, and because of the limited space available upon the machine, this fuse has been placed upon the truck together with a switch suitable to cut the current from the main circuits of the machine when emergency renders such interruption desirable. When for any reason the fuse upon the truck is blown out, a considerable amount of time required for the operator to travel from the mining machine to the truck, to hunt out a new fuse, and to install it in place of the one destroyed. These objectionable features are overcome by the present invention.

In Figure 1 of the drawings, reference numeral 5 indicates a mining machine of the class adapted to rest upon and slide over the mine floor during the mining operation, or to be loaded on the truck 6 for transportation from one working place to another. The mining machine is actuated by an electric motor 7 Figure 2, adapted to receive its actuating current through a suitable flexible conductor cable 8 extending between the mining ma chine and the auxiliary controlling devices upon the trucln The truck thus serves as a base in the vicinity of which the mining machine may be moved to perform its cutting function.

Truck 6 is equipped with a cable reel 9 upon which is wound a conductor cable 10 comprising a pair of conductors 11 and 12 respectively connected to an overhead conductor 13 and a grounded track rail 14 as ordinarily installed in a mine entrance. Reel 9 functions automatically to Wind up or pay out cable 10 as the truck away from the point of attachment ofconductors 11 and 12.

Conductors 11 and 12 are in respective connection, through suitable devices on the truck, with conductors 15 and 16. Suitably mounted on V the truck are 'threegenerally similar switches 17, 18 and 19. Switch 17 is provided with a pivoted arm 17a carrying at its free end a contact 17 5 adapted to cooperate witha contact 17 0 at the end of conductor 15. A blow-out magnet 171i is provided for extinguishing arcs formed at the contacts. p

Contact 17?) is in electrical connection with a conductor whichleads through a blow- I and close the line out magnet 18cZ'to a fixed contact 180 of switch 18. Switch 18 has a pivoted arm 18a supporting a contact 185. I 7

Conductor 16 leads through a blow-out magnet 1945 to a fixed contact 190 of switch 19, the latter including a pivoted arm 19a with a contact 195 which is in electrical con- Inlection with a conductor 21 included in cae 8. A conductor 22 is in connection with contact 18b and has interposed in itran overload relay 23 including a switch 24 moved upon the occurrence of an overload in the line and also adapted to be manually moved to open when necessary or desired. Conductor 22 is included in cable 8. i

A contact 25 of overload relay 23 is in con- 26 and a conductor 27.

nection through a fuse with conductor 15. The free end of switch 24 may be moved on or off contact 25, the

pivoted end of the switchbeing in electrical connection through a connector 28 with conductor 16. Interposed in conductor 28 is a magnet coil 17@ for the control of arm 17a of switch'17. Arm 17a has connected .to it a post 29 of non-conductive material carrying a plate 30 adapted to bridge a gap in a conductor 31 when arm 170; is moved to bring contacts 17?) and 17 0 together. Conductor 31 is in connection with conductor 16'and has interposed in it a magnet coil 19e for the actuation of switch 19. A branch 32 in connection with conductor 31 has interposed therein a magnet coil 186 for switch 18 and is led through cable 8. r.

' Motor 7 comprises an armature 33 and field coils 34 and'35 which are connected by suitable conductors with a controller comprising 1 7 a commutatin'g cylinder .36 for the cutting in and out of a resistance 37, and a reverse cylmoves toward or inder 38. The commutating cylinder has fixed thereon a pair of similar segments 39 and 40, a segment 41, and segments 42, 43 and 44 for the cutting in and out of portions of resistance 37 the segments all being electrically connected. Fingers 45, 46, 47, 48, 49 and 50 are provided for cooperation with the commutator segments in the well known manner. v

The reverse cylinder 38 is provided with a drum on which are arranged contact plates in the well known manner, these plates c0- operating with fixed fingers 51, 52, 53 and 54. Since only plates 55 and 56 of the reverse drum enter into the typical circuit to be de scribed, it will be unnecessary to consider here the complete arrangement of the drum.

Conductor 21, which is a continuation of negative conductor 16, isconnected to finger 50 of the controller, while conductor 22 which 7 is a continuation of positive conductor 15, is in connection with field windings 34 through a connection 57. At their opposite end, windings 34 are in connection, by means of a conductor 58 with finger 51 of the reverse drum. Finger 52 of the drum is in connec tion with a brush through a conductor 59, while finger 54 is in connection with the other brush through a conductor 60. Finger 53 of the reverse drum is in connection with controller finger 49 through a conductor 61. Finger 45 of the controller is connected by means of a conductor 62 with the resistance which at its other end, by means of conductor 63, is in connection with finger 49. A blowout magnet 64 for extinguishing arcs at the commutating contacts, is interposed in conductor 63; Fingers .47 and 48 of the con troller connect into the resistance, while con-- ductor 32 is in connection with finger 46.

If the motor is to be operated, switch 24 of the overload relay is manually closed thereby connecting coil 17 6 across conductors 15 and 16 so that switch 17 is closed. I Movement of arm 17a causes plate 30 to bridge the gap in connector 31 so that coil 19a is energized, thus closing in the negative side of the line. Switch 18 remains open. r

Upon moving cylinder 36 to its first position wherein segments 39 and 40 are brought into contact with fingers 45 and 50, connection is established from the negative grounded track rail 14 through the conductor 12, conductor 16, switch 19, conductor 21, finger 50,,s'egment 40, through the intermediate segments to segment 39, finger 45, conductor 62,

. resistance 37, conductor 63, blow-out magnet 64, finger 49, conductor 61, finger 53, plate 56,

finger '54, conductor 60, armature 33, con- 52, plate'55, finger 51,con-' switch 19, the latterv being tive position brings segment 41 into contact with finger 46 thereby establishing a connection through conductor 32 to coil 186 thereby causing switch 18 to close. Further rotation of the commutating cylinder progressively cuts out sections of the resistance 37 to bring the armature to full speed in the usual and well known manner, segment 41 being of suflicient extent to remain in contact with finger 46 in all commutating positions of the cylinder.

When the cylinder is moved in the reverse direction a suflicient distance to break the contact of segment 41 with finger 46, current will be cut out of the coil 18c, thereby allowing switch 18 to open and thus arrest armature rotation.

When for any reason, such as an overload or a short circuit in the apparatus, the current flowing through the circuit shall exceed a predetermined value, the overload coil will act to move switch 24 to its open circuit position thereby breaking the connection through coil 170 to allow switch 17 to open. The opening of switch 17 enforces movement of contact element 30 to break circuit 31 thereby causing the deenergization of coils 18c and 196 and the consequent opening of switches 18 and 19. This opening of switches in both sides of the line excludes all electrical potential of whatever sign, from all the devices upon the mining machine.

A conductor of relatively high resistance is connected from the conductor 15 to conductor 20 around the contacts of switch 17 in such manner that by opening switch 17 conductor 65 adds to the resistance of the circuit to limit thereby the possible flow of current therein. By the introduction of this resistance into the circuit in series with the switches 18 and 19 at the time of opening those switches, the switch contacts will be protected from the destructive effects of arcs formed by currents greater than the normal capacity of the switches.

When it is desired to cut off the current from the devices upon the mining machine, and, for any reason, it is undesirable or impossible to operate the controller, switch arm 24 of the overload relay may be moved to its open circuit position thereby causing the opening of switches 17 18 and 19 in the manner just described.

While I have shown and described a specific embodiment of my invention, it will be understood that I do not limit myself except as determined in the following claims.

I claim:

1. In apparatus of the class described, an electric motor mounted on a grounded movable metallic support, a base in the vicinity of which the support is movable, an electrical supply line leading to the base, a flexible supply cable for the motor extending between the base and support, a controller on the support having contacts interposed in the nega-' tive lead of said supply cable, and a circuit breaker at the base interposed in the positive side of the line.

2. In apparatus of the class described, an electric motor mounted on a grounded movable metallic support, a base in the vicinity of which the supportis movable, an electrical supply line leading to the base, a flexible supply cable for the motor extending between the ase and support, a controller on the supporthaving contacts interposed in the negative lead of said supply cable, an electro-magnetic' switch at the base interposed in the positive side of the line, an actuating circuit for said switch, and means operated by the controller for controlling said circuit.

3. In apparatus of the class described, an electric motor mounted on a grounded movable metallic support, a base in the vicinity of which the support is movable, an electrical supply line leading to the base, a flexible supply cable for the motor extending between the base and support, a controller on the support having contacts interposed in the negative lead of said supply cable, said controller including a commutating cylinder,an electro-magnetic switch at the base interposed in the positive side of the line, an actuating circuit for said switch, and a switch actuated by said cylinder prior to its commutating action to control said circuit.

4. In apparatus of the class described, an electric motor, a motor controller including a commutating cylinder and cooperating contacts therefor, a supply line for said motor, the controller contacts being in connection with the negative side of said line, a switch in each side of the line remote from the controller, means operated by the controller prior to the commutating action of its cylinder to close the switch in the positive side of the line, and means actuated upon an overload to automatically open both of said switches independently of the controller.

5. In apparatus of the class described, an electric motor, a motor controller including a commutating cylinder and cooperating contacts therefor, a supply line for said motor, the controller contacts being in connection with the negative side of said line, a switch in each side of the line remote from the controller, means operated by the controller prior to the commutating action of its cylinder to close the switch in the positive side of the line, means actuated upon an overload to automatically open both of said switches independently of the. controller, and manually operable means r'or opening said switches.

6. In apparatus of the class described, an electric motor, a motor controller including a commutating cylinder and cooperating contacts therefor, a supply line for said motor, the controller contacts being in connection with the negative side of said line, a switch in each sideof the line remote-from'the controller, means operated by the controller prior to the 'commutating action of its cylinder to close the switch in the positive side of the line, switches independently of the controller, and

means for automatically increasing the re-' sistance in the line immediately prior to the opening of said switches.

7. In apparatus of the class described, an electric motor, a supply line for said motor, an overload relay in the line, a circuitbreaker in the line and controlled'by said relay, an

electro-magnetic switch in each side of the line, and means controlled by the circuit breaker for controlling said circuit. 1

8. In apparatus of the class described, an electric motor, a supplyline for said motor, an overload relay in the line, a circuit breaker in the line and controlled by said relay, an electro-magnetic switch in each side of the line, an energizingcircuit for said switches, means controlled by the circuit breaker for controlling said circuit, and a resistor con nected in said line around said circuit breaker. the class described, an a supply line for said motor,

9. In apparatus of electric motor, a controller for sa1d motor including a commutating cylinder and cooperating contacts therefor,

the controller contacts being in connection with the negative side of-the line, an overload relay in the line, a circuit breaker in the line andcontrolled by said relay, an electro-magnetic switch in each side of the line remote from the controller, an energizing circuit for said switches, means operated by the controller prior-to the commutating action of its cylinder to close theswitch in the positive side of the line, and means operable to open said circuit independently of the controller.

10. In apparatus of the class described,'an electric motor, a supply line for said motor,

a controller for said motor including a come mutating cylinder and cooperating contacts therefor, the controller nection With the negative side of the line, an overload relay in the line, a circuit break er in the line and controlled by said relay,

an electro-magnetic switch in each side of the line remote from the energizing circuit for said switches, means operated by the controller prior to the commutating' action of the cylinder to close the switch in the positive side of the line, means operable to open said circuit independently of the controller. and a resistor connected in said line around said circuit breaker.

11. In apparatus of theclass described, an

' electric able metallic support, a base in the vicinity of which the support is movable, an electrimotormounted on'a grounded movcal supply line leading to the base, a flexible supply cable for the-motor extending he means operable to open both of said an energizing circuit for said switches,

contacts being in con-- tween the base and support, a controller on the support including a commutati'ng cylinder and cooperating contacts therefor, the negative lead of said cable being in connection with said contacts, an overload relay in the line at the base, a circuit breaker in the line at the base and controlled by said relay, an electro-magnetic switch in each side of theline at the base,v an energizing circuit for said switches, means operated by the con; troller prior to the commutating action of its cylinder to close the switch in the positive side of the line, and means operable by the circuit breaker to open said circuit. 7

12. In apparatus of the class described, an electric motor mounted on a grounded movable metallic support,'a base in the vicinity of which the support is movable, 'anelectrical supply line leading to the base, a'flexi'ble supply cable for the motor extending between the base and support, a controller on the support including a commutating-cyL 'inder and cooperating contacts therefor, the

negative lead of said cable being in connec-' tion with said contacts, an overload relay in the line at thebase, a circuit breakerin the line at the base and controlled by said relay, an electro-magnetic switch in each side ofthe line at the base, an energizing circuit for said switches, means operated by the controller prior to the commutating action of its cylinder to close the switch in the positive side of the line, means operable by the circuit breaker to open said circuit, and a resistor con nected in said 7 line around said circuit breaker. i r

In testimony whereof I have hereunto set my hand. i V

r I NILS D. LEVIN. 

